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Biomedical subjects

J Hill

Publications and source records attributed to J Hill.

At least 343 records · Page 19Linked to original sources
PubMed1986

The androgen status of aging male rhesus macaques.

Whether the rhesus male experiences changes in the dynamics of testosterone (T) and LH secretion with age was investigated in six young (6-8 yr old; 7-12 kg) and six aged (22+ yr old; 9-11 kg) intact rhesus males. Each male was fitted with an indwelling jugular catheter, which was attached to a cranial platform and stainless steel cable tether. Catheters passed from a swivel device at the top of each cage through a wall to an adjoining room. On four occasions, 1.0-ml blood samples were obtained from each male every 20 min for 24 h for plasma T RIA and plasma LH bioassay. Plasma T and LH data were analyzed by the PULSAR program to detect hormone peaks. Mean 24-h plasma T levels were similar in young and aged males as were the pulse amplitudes of T; however, the pulsatile pattern of T concentrations was different between young and aged males. Young males displayed a marked nocturnal increase in both T concentration and number of T pulses. Aged males demonstrated a significant nocturnal elevation of plasma T concentration, but displayed a significant nocturnal diminution in both concentration and numbers of T pulses compared with young males at night. Although LH concentrations and the total number of LH pulses per 24 h were similar in young and aged males, marked age-related alterations were evident in the pulsatile pattern of LH levels. Unlike young males, aged males failed to display a daytime reduction in the number of LH pulses. Our data point to coexistent changes in hypothalamic sensitivity to the negative feedback effects of T and testicular responsiveness to LH as a function of age in the rhesus macaque.

Aging↗
PubMed1986

Loss of enhanced nocturnal growth hormone secretion in aging rhesus males.

Enhanced nocturnal release of GH is decreased with aging in man, a change that may implicate GH in a general decline in anabolic metabolism associated with aging. The aim of this study was to determine whether nonhuman primates experience an age-related reduction in plasma GH levels by comparing the 24-h patterns of GH secretion in unrestrained young and aged male rhesus monkeys. Six young (8 yr old) and six aged (22+ yr old) intact rhesus males were fitted with indwelling jugular catheters, cranial platforms, and stainless steel cable tethers. Catheters passed from a swivel device at the top of each cage through a wall to an adjoining room. On four occasions, 1.0-ml blood samples were obtained from each male every 20 min for 24 h for plasma GH RIA. Plasma GH data were analyzed by the PULSAR program to detect hormone peaks. Mean 24-h plasma GH was less (P less than 0.0005) in aged males [0.84 +/- 0.04 ng/ml (+/-SEM)] than in young males (1.37 +/- 0.09 ng/ml). Likewise, the amplitudes of GH pulses were less (P less than 0.001) in aged males than in young males. Although no circadian pattern of GH concentrations was apparent in either age group, young males displayed more (P less than 0.05) nocturnal GH pulses (5.73 +/- 0.41 pulses/12 h) than those occurring during lights-on (3.09 +/- 0.32 pulses/12 h). The numbers of GH pulses in aged males (4.00 +/- 0.63 pulses/12 h) were similar to those in young males during lights-on, but aged males showed fewer (P less than 0.05) nocturnal GH pulses (4.27 +/- 0.47 pulses/12 h) than did young males. The duration of GH pulses in aged males (53.6 +/- 5.0 min) was similar to that in young males (50.6 +/- 5.0 min) during lights-off. Young males showed an extended (P less than 0.001) GH pulse duration (88.8 +/- 8.8 min) during lights-on that was not evident in aged males (66.2 +/- 5.4 min). These data demonstrate that unrestrained young rhesus males experience an enhanced nocturnal release of GH in terms of pulse frequency, and as in humans, this enhanced nocturnal release of GH is diminished with age. In addition, rhesus males experience, as do humans, a reduction in circulating GH levels as a function of age.

Aging↗
PubMed1986

5-Aminosalicylic acid or sulphapyridine. Which is the active moiety of sulphasalazine in rheumatoid arthritis?

Thirty patients with active rheumatoid arthritis participated in an open study of 6 months' treatment with either 5-aminosalicylic acid or sulphapyridine, the two moieties of sulphasalazine. Patients were assessed at regular intervals using a number of clinical and biochemical tests designed to detect specific antirheumatic activity. Patients taking sulphasalazine showed significant improvement in most parameters of disease activity, but those taking 5-aminosalicylic acid did not improve despite the fact that high serum concentrations of 5-aminosalicylic acid and acetyl 5-aminosalicylic acid were achieved. These results suggest that sulphapyridine is the active moiety of sulphasalazine. Its possible mode of action is discussed. Nausea was a frequent problem in patients taking sulphapyridine. Unless this problem can be overcome, sulphapyridine is unlikely to offer any therapeutic advantages over sulphasalazine in the treatment of rheumatoid arthritis.

Adult↗
PubMed1986

In search of basic values.

To make ethical decisions, people must be able to assign priorities to competing values. Although health professionals are expected to assign the highest priority to the value of a healthy citizenry, in this period of economic constraint, creating and reinforcing that value is problematic for many health care managers. Their dominant premise--financial survival--conflicts with the basic premise of most physicians and nurses--service to the client. Despite this problem, leaders, now more than ever, must take responsibility for a reexamination of the purpose of health care. If they do not, a new round of government regulation will be initiated to protect patient groups that may be neglected, particularly the indigent, the elderly, and the chronically ill. Training for this responsibility may be accomplished through a humanities component in undergraduate and graduate foundation courses, continuing education workshops and conferences, and leadership task forces that address short-term institutional goals and long-term national objectives.

Education, Continuing↗
PubMed1986

A study to determine the active moiety of sulphasalazine in rheumatoid arthritis.

Thirty patients with active rheumatoid arthritis (RA) participated in an open study of 6 months' treatment with either 5-aminosalicylic acid (5-ASA) or sulphapyridine (SP), the two moieties of sulphasalazine (SASP). Patients were assessed at regular intervals using clinical and biochemical tests designed to detect specific antirheumatic activity. Patients taking SP showed significant improvement in disease activity, but those taking 5-ASA did not improve, despite the fact that high serum concentrations of 5-ASA and acetyl 5-ASA were achieved. These results suggest that SP is the active moiety of SASP. Its possible mode of action is discussed. Nausea was a frequent problem in patients taking SP. Unless this can be overcome, SP is unlikely to offer any therapeutic advantages over SASP in the treatment of RA.

Adult↗
PubMed1985

Cloning and characterization of the yeast nuclear gene for subunit 5 of cytochrome oxidase.

The nuclear gene COX5 coding for subunit 5 of cytochrome oxidase has been cloned by transformation of the cox5-1 mutant aE4-238/AL1 with a library of yeast genomic DNA. The recombinant plasmid pG46/ST2 bearing a nuclear DNA insert of 1.17 kilobase pairs restores the ability of cox5 mutants to respire and to synthesize a wild type subunit 5. The COX5 gene has been sequenced and determined to code for a 153-amino acid long protein with a molecular weight of 17,121. The amino-terminal 20 residues comprise the signal peptide. The sequence starting from residue 21 matches the partial sequence reported for the mature subunit 5. The sequence of the subunit 5 gene indicates that the mature protein has a molecular weight of 14,858 which agrees with previous size estimates based on electrophoretic migration. The primary sequence and polarity profile of yeast subunit 5 establishes that it is homologous to subunit 4 of bovine cytochrome oxidase.

Amino Acid Sequence↗
PubMed1985

A mutation in yeast mitochondrial DNA results in a precise excision of the terminal intron of the cytochrome b gene.

The yeast nuclear gene CBP2 was previously proposed to code for a protein necessary for processing of the terminal intron in the cytochrome b pre-mRNA (McGraw, P., and Tzagoloff, A. (1983) J. Biol. Chem. 258, 9459-9468). In the present study we describe a mitochondrial mutation capable of suppressing the respiratory deficiency of cbp2 mutants. The mitochondrial suppressor mutation has been shown to be the result of a precise excision of the last intervening sequence from the cytochrome b gene. Strains with the altered mitochondrial DNA have normal levels of mature cytochrome b mRNA and of cytochrome b and exhibit wild type growth on glycerol. These results confirm that CBP2 codes for a protein specifically required for splicing of the cytochrome b intron and further suggest that absence of the intervening sequence does not noticeably affect the expression of respiratory function in mitochondria.

Base Sequence↗
PubMed1985

Colostomy wound closure.

The management of the wound at the time of colostomy closure has been controversial, and wound infection is a frequently cited complication of this procedure. We have conducted a prospective randomized study of colostomy wound closure in 105 patients with three study groups: (1) primary closure (n = 38); (2) primary closure with subcutaneous drains (n = 29); and (3) delayed primary closure (n = 38). All patients had mechanical bowel preparation with whole gut lavage as well as oral neomycin sulfate/erythromycin estolate and perioperative parenteral cefazolin sodium (Ancef). Five wound infections (4.8%) occurred. Three infections were in the delayed primary closure group and one infection in each of the other two study groups. No statistical difference in wound infection was demonstrated. On the basis of the findings in this study, we would not recommend delayed primary closure for the management of colostomy closure wounds when careful mechanical and antibiotic preparation has been utilized.

Adult↗
PubMed1985

Canine neuroendocrine carcinoma. A tumor resembling histiocytoma.

The clinical and light- and electron microscopic features of 20 cases of canine neuroendocrine carcinoma, initially classified as atypical histiocytomas, are reported. The locally expansile well-circumscribed dermal tumor nodules were composed of solid masses of cells with high mitotic index and multinucleation, arranged in a trabecular pattern with prominent fibrovascular connective tissue stroma rich in reticulin fibers that outlined compact cell nests. Ultrastructural studies revealed evenly dispersed chromatin, focally indented nuclei and abundant cytoplasm with perinuclear filaments, membrane-bound dense core granules, and prominent interdigitating plasma membrane projections with primitive intercellular junctions. Clinical and pathological comparisons between canine neuroendocrine carcinoma, canine histiocytomas, and human Merkel cell neoplasms are discussed.

Age Factors↗
PubMed1985

A double-blind controlled trial of etretinate (Tigason) and ibuprofen in psoriatic arthritis.

Etretinate (Tigason) and ibuprofen have been compared in a double-blind controlled trial in psoriatic arthritis to see if we could confirm a specific action for this vitamin A derivative suggested from earlier uncontrolled studies. Eleven out of 20 patients completed 24 weeks of therapy with etretinate (up to 0.5 mg/kg/day) whereas only 1/20 patients completed 24 weeks of therapy with ibuprofen alone. Etretinate improved skin lesions, and this may have encouraged patients to persist with it. Improvement of statistical significance was seen for articular index in both groups. In addition significant improvement in ESR, haemoglobin, C-reactive protein, and histidine occurred in the etretinate group. The main side effects of etretinate (which may preclude its use at a higher dose in this condition) included cracked and dried lips and sore mouth.

Adolescent↗
PubMed1985

A comparison of faecal blood loss caused by tenoxicam and piroxicam in normal healthy male volunteers.

Faecal blood loss arising from tenoxicam at a dose of 20 mg/day was compared to that arising from piroxicam at a dose of 20 mg/day in a double-blind, parallel comparative study in 12 healthy male volunteers. Faecal blood loss was measured for a 1-week run-in on placebo, during 4 weeks of treatment and for a 2-week post-treatment period in both groups. Plasma levels for tenoxicam and piroxicam confirmed good compliance in all subjects. Mean blood loss during the placebo run-in period was 0.35 ml/day. Mean blood loss during treatment with tenoxicam was 0.84 ml/day and with piroxicam 0.81 ml/day. There was no significant difference between these measurements. On cessation of treatment, faecal blood loss continued both in the tenoxicam group (mean 1.30 ml/day) and piroxicam group (mean 1.41 ml/day). The difference between these was not statistically significant. No significant haematological or biochemical abnormality resulted from either of the two trial drugs during the period of the study. Urinalysis and NAG/creatinine ratio also remained unaltered in both treatment groups.

Adult↗